(a) Technical Field of the Invention
The present invention generally relates to chairs, and more specifically to an assembly for adjusting the elevation of a chair's backrest to a number of predetermined positions.
(b) Description of the Prior Art
To provide comfortable seating, a chair's backrest should be designed with a curved cushion which leans slightly backward for supporting a sitter's waist and back. Further more, as each person has his or her own physical characteristics, the vertical position of the backrest should be adjustable to fit the sitter's specific posture. However, currently most adjustable chairs found in offices only allow a sitter to adjust the degree of reclining of the backrest and the backrest usually has a fixed vertical position based on the average posture of an ordinary person.